Accuracy of crowns based on digital intraoral scanning compared to conventional impression—a split-mouth randomised clinical study
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The aim of this prospective in vivo study was to evaluate the accuracy of the marginal and internal fit of crowns based on conventional impression (CI) or intraoral scan (IOS) in a randomised, split-mouth set-up.
Materials and methods
Nineteen patients needing full coverage crowns, fitting a split-mouth design, were provided with two lithium disilicate crowns: one based on a CI and one based on an IOS. The marginal and internal accuracy of the crowns were assessed with the replica technique and clinically using a modified California Dental Association (CDA) quality evaluation system.
At the preparation margin, the median gap was 60 μm for IOS and 78 μm for CI. For the other points, the median gap ranged from 91 to 159 μm for IOS and 109 to 181 μm for CI. The accuracy of the IOS was statistically significantly better at all point except at the cusp tip. All crowns where rated R or S at both the 6- and 12-month follow-up appointments. The results for the clinical evaluation with CDA for marginal integrity showed no statistically significant difference between the two impression methods at both the 6- and 12-month evaluations.
Crowns based on IOS show statistically significantly better marginal and internal adaptation before cementation compared to conventional impression. However, the clinical evaluation showed similar marginal adaptation.
Crowns based on a fully digital workflow can provide clinically acceptable marginal adaptation, comparable to crowns based on CI.
KeywordsDental impression technique Intraoral scanning Digital impression CAD/CAM Dental crown Clinical accuracy
The work was supported by the Faculty of Health and Department of Dentistry and Oral Health, University of Aarhus, Denmark.
Compliance with ethical standards
This clinical trial was approved by The Regional Scientific Ethical Committee, (reference number 44868) and was conducted in accordance with the Declaration of Helsinki and internationally accepted guidelines for RCT, including the CONSORT statement (www.consort-statement.org).
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in this study involving human participants were in accordance with the ethical standards of the national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all individual participants included in the study.
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